The present invention is concerned with the measurement or analysis of the primary and/or secondary structure of nucleic acids as well as the concentration, type and molecular weight thereof. The invention also provides a method for the separation and recovery of various nucleic acids from a mixture thereof in solution.
Known methods for analysis include UV, CD or fluorescence spectroscopy. These methods, however, often are complex and require decomposition of the polymer and/or the use of chromatography. Decomposition of the polymer, if required, precludes simple recovery. Furthermore, the known methods measure only one property at a time.
The inventive method utilizes precipitation of nucleic acids. Interactions between aromatic cations and nucleic acids at high binding density and high concentration of the ligand are known to often result in the precipitation of the product. Although this phenomenon was observed earlier (Kapuscinski et al Cytometry 2 201-211 (1982) and references cited therein), the conditions of the precipitate formation were not studied in detail and no attempt was made to characterize the molecular structure of these complexes. Rather, the precipitation was treated as a hindrance in the titration experiments which were normally analyzed by spectroscopic techniques and the titrations were usually terminated when precipitation occured.